Audio Board - ViewSonic VX800-3 - 18" LCD Monitor Service Manual

1.5 DDC 1/2 B
IC600 (24LC02) & IC602 (24LC21A) can continuously transmit its extended identification,
"EDID" using DDC1 communication channel. In addition, the monitor can respond to a request
for EDID, or complete VDIF, to be transmitted using DDC2, level B commands. Pin6 SCL is
clock input for DDC 2B, pin5 SDA for data input, and pin7 VCLK is clock input for DDC1.
In DDC1 data transfer (UNI-directional mode), the VCLK input pin is used as an input
clock for data transmission and SDA output pin is used as serial data line the SCL pin will
hold high. The DDC2B node (BI-directional mode) BUS consists of two wires. SCL is for
the data transmission clock and SDA is for the data line.

3.2 Audio Board

2.1 Audio processor
ICA2 (PT2313L) is a four-channel digital audio processor utilizing CMOS
Technology .Volume, Bass, Treble, Balance, Front/Rear Fader Processor are
incorporated into a single chip. Loudness function and Selectable input gain are also
provided to build a highly effective electronic Audio processor having the highest
performance and reliability with the least external components. And all functions are
programmable using the IIC BUS
PIN# PIN NAME I/O
1 REF
2 VDD
3 Agnd
4 Treb_L
5 Treb_R
6 RIN
7 Rout
8 Loud_R
9 Rin 3
10 Rin 2
11 Rin 1
12 Loud_L
13 Lin 3
14 Lin 2
15 Lin 1
16 LIN
17 Lout
ViewSonic Corporation
DESCRIPTION
- Analog reference voltage(1/2 VDD)
- Supply input voltage
- Analog ground
I Left channel input for treble control
I Right channel input for treble control
I Audio processor right channel input
O Gain output&input selector for right channel
I Right channel loudness input
I Right channel input 3
I Right channel input 2
I Right channel input 1
I Left channel loudness input
I Light channel input 3
I Light channel input 2
I Light channel input 1
I Audio processor left channel input
O Gain output and input selector for left
channel
Confidential – Do Not Copy
VX800-3